Long-term stress corrosion crack (SCC) initiation behavior in cold-worked Alloy 690 is being evaluated by constant load tensile testing in 360°C simulated pressurized water reactor primary water. Seven commercial Alloy 690 heats with different starting microstructures and cold-work levels are being tested at either 90% or 100% of the material yield stress (YS). Grain boundary (GB) cavities had previously served as the key precursor to crack initiation in two thermally treated (TT) and highly cold worked (CW) Alloy 690 materials featuring the most susceptible GB carbide distribution to cavity formation and growth. Macroscopic crack initiation was detected in these specimens within ~2.5 years of exposure at 100%YS. As the test progressed, short IG crack formation or macroscopic crack initiation was observed in a few more material/loading conditions. In this paper, characterization results acquired at recent test interruptions will be reported with a focus on specimens that exhibited an increased GB damage over time. Quantitative data has been obtained to predict GB cavity evolution as a function of time in highly CW Alloy 690TT materials with susceptible GB microstructure. In addition, GB damage characteristics in specimens with different loading conditions, cold work levels, or thermal-mechanical history were compared and discussed.